Valve for rock drills



Dec. 11 1928.

E. B. LEAR VALVE FOR ROCK DRILLS j If f'P 0W Filed Aug. 50, 1927 IN V EN TOR.

H15 T RNE).

Patented Dec. 11, 192 8.

UNITED STATES.

I V 1,694,882 PATENT OFFICE.

EARL B. LEAR, OF PHILLIPSBURG, NEW JERSEY, ASSIGNOR TO INGERSOLL-RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

VALVE FOR ROCK. DRILLS.

Application filed August 30, 1927. Serial No. 216,403.

This invention relates to rock drills, but more particularly to a distributing valve for fluid actuated rock drills of the hammer type. The objects of the invention are to eflect a 6 rapid distribution of the pressure fluid to the cylinder, to produce a rugged valve capable of withstanding the severeusage to which valves of this type are subjected, and to obtain a positive action of the valve.

Other objects will be pointed out hereinafter, and to all of these ends the invention consists of the combination of elements and arrangement of parts havin the general mode of operation substantially as herein-' after described and claimed and illustrated in the accompanying drawings, in which- Figure 1 is a longitudinal elevation in section of so much of a rock drill as will serve to illustrate the invention, showing the valv in one of its extreme positions, and

F'gure 2 is a view similar to Figure 1,

showing the valve in its other extreme position.

Referring more particularly to the drawings, A designates a c linder having a free exhaust port B contro led by a piston C reciprocable in the cylinder A. The ends of the cylinder A may be sealed in any suitable manher. In the drawings, a front cylinder Washer D serves this function at the front end of the cylinder A and inv the rearward end of the cylinder is disposed a back cylindcr washer E bored in this instance to receive a rifle bar F which extends into and engages the piston C in'a well known manner for impartmg rotary movement to the piston. In accordance with the present invention, the cylinder A is provided with a valve chest G having a cylindrical bore H ofsubstantially 40 uniform diameter throughout its length. In t the ends of the bore H are; disposed plugs J and K held in operative position by means of bolts L. At the outer ends of the plugs J and K are formed flanges O which bear against the ends of the valve chest G to limit the distance which the said plugs J and K may extend into said valve chest. The inner or adjacentends of the plugs J and K in this instance are suitably spaced with respect to each other to permit the passage of pressure fluid therebetween into the valve chamber P.

The valve chamber P in this instance comprises an enlarged central portion Q, and reduced end portions R and S formed in the 6 plugs J and K respectively.

From the end portion R of the valve chamber extends an inlet passage T leading to the rearward end of the cylind er for conveying pressure fluid thereto to actuate the piston C in a forwardly direction. Similarly, from the rearward end portions of the valve chamber P leads an inlet passage U which terminates at its outlet end in the front end of the cylinder for conveying pressure fluid thereto to impel the piston C rearwardly.

Disposed within the valve chamber 1 isa distributing valve V having endprojections W and X guided by the reduced end portions R and S respectively of the valve chamber P. The ends Y and Z of the projections W and X constitute holding surfaces against which pressure fluid in passin to the ends of the cylinder may act for hol ing the valve in its extreme POSlt-iOIlS.

Intermediate the ends of the valve V is formed an external flange 'b of substantially the same diameter as the central portion Q of the valve chamber. Therfront and rearward ends of the flange b constitute actuating surfaces 0 and d against which pressure fluid admitted through kicker passages e and 7 may act for actuating the valve. As will be observed the kicker assage e leads from a point in the cylinder orwardly of the free exhaust port B to the front end of the enlarged portion Q, of the Valve chamber and the kicker passage f leads from a point rear wardly of the exhaust port B to the rearward end of the enlarged portion Q of the valve. chamber. The kicker. passages eand f are controlled entirely by the piston C whereby they are uncovered: at the proper period in the cycle of operations for admitting pressure fluid into the valve chamber.

The flange Z) is preferably of considerable length to permit the formation therein of front and rearward admission passages g and h for the passage of pressure fluid into bores jand 7:: formed in the projections W and X and are divided by a wall V in the valve V.

- Pressure fluid for operating the drill may be conveyed from a suitable source of supply (not shown) to a connection -0 in the valve chest having a port p which opens into an annular supply passage q encircling the enlarged portion Q of the valve chamber.

In order to insure against cushioning of the valve V as it approaches its extreme positions, the plugs J and K are provided with suitable leak passages 1' which lead from the ends of the enlarged portion Q, to the atmosphere.

The operation of the device is as follows: With the'valve in its extreme rearward position, illustrated in Figure 1, pressure fluid from the supply chamber 9 passes through the admission passage g, the bore j and through the inlet passage T into the rearward actuating surface (1 will throw the valve V forward ure 2.

However, while the piston C is travelling forwardly and after it covers the exhaust port B the air inthe front end of the cylinto the position illustrated in Figder A will be compressed and such compres-v sion flowing through the inlet assage U and the bore 1:. will act against t e wall V of the vvalve V to augment the live pressure fluid acting against the actuating surface (1 to throw the valve V forwardly.

Withthe valve in its forward extreme position, pressure fluid will flow through theadmission passage h, the bore '71:, thence through the inlet passage U to the frontend of the cylinder to actuate the piston C rearwardly. As the piston C is travelling rearwardly, the kicker passage 6 will be uncovered thereby to admit pressure fluid into the front end of the enlarged portion Q of the valve chamber for throwing the valve V to its initial position. During thisstroke of the piston C the air in the rearward end of the cylinder A will of course also be compressed and such compression passing through the inlet passage '1 and the bore will act against the front surface of the wall V and assist in throwing the valve rearwardly.

I claim:

-1..In a fluid actuated rock drill, the combination of a cylinder and piston, a valve chest having a valve chamber and a supply chamber, inlet passages leading from the valve chamber to the cylinder, a distributing valve in the valve chamber, said valve having bores inits ends and admission passages opening into the boxes for admitting pressure fluid from the supply chamber into the inlet passages and kicker passages conveyin pressure fluid from the cylinder to the va ve chamber for actuatin the valve.

2. In a fluid 'actuatedroc drill, the combination of a cylinder and piston, a valve chest having a valve chamber and a supply hortly prior to the uncovering" for actuatin chamber, inlet passages leading from the valvechamber to the cylinder, a distributing valve in the valve chamber having a central flange and reduced end projections, said projections having bores for conve ing pressure fluid to the inlet passa es, a mission passages in the flange afl'or ing communication between the supply chamber and the bores, and kicker passa es in the valve chest conveying pressure uid from the cylinder into thevalve chamber to act against the flange the valve. a

3. In a fluid actuated rock drill, the com bination of a cylinder and piston, a valve chest having a valve chamberand a supply chamber, said valve chamber comprising an- I enlarged central portion and reduced vend portions, inlet passages leading fromthe end portions to the cylinder, a distributing valve in the valve chamber having acentral flange and reduced end projections,,said projections having bores for conveying pressure fluid to the inlet passages, admission passages in the flange afl'ordin'g communication between the supply chamber and the bores, said admission passages being movable into and out of registry with the supply chamber, and

kicker passages in the valve chest conveyingpressure fluid fronithe cylinder into the en- .larged portion of the valve chamber to act against the valve for actuating said valve,

said kicker piston.

4. In a fluid actuated rock drill, the combination of a cylinder and piston, a valve chest-having a valve chamber and a supply chamber, said valve chamber comprising an enlarged central portion and reduced end portions, crossed inletv passages leading from the end portions to the cylinder, a distribpassages being controlled by the uting valve in the-valve chamber having end projections with holding surfaces exposed intermittently to pressure fluid for holding the valve, said projections having bores for conveying ressure fluid to the inlet passages, a central ange on the valve having admission passages aflordin communication between the supply chamber and'the bores, actuating surfaces on the ends of the flange,

'cker passages in the valve chest conveying pressure fluid from the cylinder into the en,- larged portions vof the valve chest to act against the actuatin'g surface for actuating the valve, and leak passages in the valvechest venting the ends of the enlarged portion of the valve chamber to the atmosphere.

In testimony whereof I have signed this specification. I

EARL B. LEAR.

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